Thermal circuit-controller.



F. KUHN.

THERMAL CIRCUIT CONTROLLER.

' APPLICATION FILED HIM-8.1913.

i,210,331. Patented Dec. 26,1916.

Z ELllI/IIIIlW/A in, 7; F

' elements and the FRANK KUHN, OF DETROIT, MICHIGAN.

THERMAL craourr conrnomnn.

Specification of Letters Patent.

Patented Dec. 26, 1916.

Application filed March 8, 1913. Serial No. 752,876.

Toall whom it may concern Be it known that I. FRANK KUHN, a citizen ofthe United States of America, residing at Detroit, in the county ofWayne and State of Michigan, have invented certain new and usefulImprovements in Thermal Circuit-Controllers, oi? which the following isa specification, reference being had therein to the accompanyingdrawings.

The invention relates to automatic cutouts for electric circuits and isparticularly designed for use in connection with electric heaters.

manner.

In the drawings: Figure 1 1s a'longitudlnal section through a portion ofan electrically heated sad iron which my improvement is applied andshowing the. circuit cut out. Fig. 2 is a perspective view showing thecup for the fusible metal and the detent wheel locked thereby. Fig. 3 isa view similar to Fig. 1 with the parts in circuit closing position.

A is the base of a sad iron which, as shown, is heated by a flat heatingunit B between said base and a heat-absorbing and distributing plate 0.v

D the hood or cover for the body, and E is a terminal contact passingoutward through-said hood and which is connected with the electricalterminals of the unit.

My improved automatic cut-out comprises a cut-out switch which ispreferably interposed between one of the external contact heating unit,and, as shown,'is housed within the hood D above the distributing plateC. In detail,- it comprises twospaced and parallelresilient contactmembers F and F which are respec-" tively connected to the externalterminal contact E and the terminal member G,'which connects directlywith the unit B. The contact members F and F may be formed of sheetmetal which is bent to extend laterally within the hood, the two membersbeing mechanically connected to each other bya bolt or rivet H which iselectrically insulated to prevent short circuiting.

The contact members F and F in the the tension of the spring M,

that as soon as said wheel is released by the normal or closed positionof the circuit are electrically connected to each other by a bridgecontact member I which is mounted upon but insulated from a carrying-armJ projecting downward from a slide K which is mounted in a suitablehousing L on top of the hood D. The slide K is further provided with aspring M for yieldably drawing the same in a direction to separate thebridge contact I from the contact members F and F. There is also a latchdog N upon the slide adapted to engage with a ratchet wheel 0 which isnormally immovable and forms a detent for holding the slide and bridgecontact I in a position to close the circuit. The ratchet wheel 0 islocked from rotation by fusible metal. which is placed in a cup member Pupon which said ratchet wheel is mounted and this cup member is placedin a recess Q in the member C or in some other suitable location whereit will be subjected to the heat developed by the unit.

With the construction as described when the parts are assembled, asshown in Fig.

1, the slide K is in a position which separates the bridge contact Ifrom the spaced contact members F'and F and therefore the heater circuitis open. To close the circuit the operator moves the slide by means of aknob R so as to engage the latch dog N with one of the teeth of theratchet wheel 0, which latter being immovable serves to hold the slidefrom return movement. This will close the electric circuit by bridgingbetween the contact members F and F and the parts will remain in thisposition during normal operation, as the heat developed will beinsufiicient to melt the fusible= metal. If, on the other hand, theinstrument becomes over-' heated-as for instance by leaving on thecurrent when not in use-the heat will actemperature of theheat-distributing body the melting point of the fusible metal held inthe cup P As thelatch dog N is constantly pressed against the ratchetwheel by it is obvlous meltingof the fusible 'metal, it will be turnedupon its pivot S, freeing the dog N and permitting the slide K- toassume a. position where the bridge contact I is withdrawn from thecontacts F and F and the circuit is broken.

In all positions of adjustment of the wheel there will be one or more ofits teeth in 2. A thermal circuit controller comprising a receptacle, afusible element therein and a tooth member controlling an electricswitch adjacent said receptacle and having a portion of the teethengaging said fusible element, said fusible element holding, said toothmember from movementwhen solidified and releasing the same when fused.

In testimony whereof ll affix my signature in presence of two witnesses.

FRANK Kill-IN.

Witnesses:

JAMES P, BARRY, HENRI E. BOWMAN.

